The present invention relates to a magnetic disk drive, as well as a wiring connection structure and a terminal structure in the magnetic disk drive. Particularly, the present invention is concerned with a terminal structure and a wiring connection structure both able to attain a stable electric connection between terminals of a flexible printed circuit board and terminals of a wiring trace in a head suspension assembly, as well as a magnetic disk drive using those terminal structure and wiring connection structure.
With the recent tendency to the reduction in size of hard disk drives, the design and manufacture of various portions of a suspension for moving a magnetic head are becoming more and more difficult. In particular, the work for electrically connecting terminals of a flexible printed circuit board connected to an electronic part which is for controlling the operation of a magnetic disk drive and data transfer and terminals of a wiring trace in a head suspension assembly is now an important process which dominates product yield and reliability. Two types of methods are mainly adopted for the electric connection. According to the first method, the terminals of the flexible printed circuit board and the terminals of the wiring trace in the head suspension assembly are connected together somewhat apart through a solder bridge. According to the second method, both terminals are connected together in a contacted or sufficiently approached state by soldering or by ultrasonic bonding.
For mass production in accordance with the first method it is necessary to use an apparatus for melting and solidifying solder in a bridge shape. In case of adopting the second method, it is possible to effect mass production even by manual operation.
FIG. 7 is a plan view showing a multi-connector provided at one end of a wiring trace, in which (A) is a plan view of a soldering iron contacting side and (B) is a plan view of a side for contact with a flexible printed circuit board. A wiring trace 500 used in the second method comprises an insulating layer 502, four conductor patterns 503a, 503b, 503c, and 503d, and a cover layer 504. The four conductor patterns are arranged side by side on a surface of the insulating layer 502. The cover layer 504 is formed on surfaces of the conductor patterns 503a, 503b, 503c, 503d and the surface of the insulating layer 502 so as to cover the conductor patterns 503a, 503b, 503c, and 503d. The wiring trace 500 is provided at one end thereof with a multi-connector 501. The multi-connector 501 is provided with four terminals 505a, 505b, 505c, and 505d at equal intervals in a longitudinal direction of the conductor patterns 503a, 503b, 503c, and 503d. The terminals 505a, 505b, 505c, and 505d are portions of the conductor patterns 503a, 503b, 503c, and 503d, respectively, and are formed as somewhat wide patterns at front ends of the conductor patterns. In the insulating layer 502 of the multi-connector 501 is formed a single rectangular aperture 506 so that the four terminals 505a, 505b, 505c, and 505d are partially exposed from the aperture. A cover layer 504a of the multi-connector 501 is formed separately from the cover layer 504 of the wiring trace 500. In the cover layer 504a, as is the case with the insulating layer 502 of the multi-connector 501, a single rectangular aperture 507 is formed in the cover layer 504a so that the four terminals 505a, 505b, 505c, and 505d are partially exposed from the aperture.
FIG. 8 is an explanatory diagram showing a connection structure in which the terminals 505a, 505b, 505c, and 505d of the multi-connector 501 are soldered onto terminals 602a, 602b, 602c, and 602d of a flexible printed circuit board 600. The terminals 602a, 602b, 602c, and 602d are provided on end sides of conductor patterns 601a, 601b, 601c, and 601d serving as four lead wires. The multi-connector 501 is bent from the wiring trace 500 so that the aperture 506 of the insulating layer 502 (see FIG. 7) faces up, and is placed on the flexible printed circuit board 600. In FIG. 8, for convenience' sake, the conductor patterns 601a, 601b, 601c, and 601d of the flexible printed circuit board 600 are represented by solid lines except the portion covered with the multi-connector 501.
The terminals 505a, 505b, 505c, and 505d of the multi-connector 501 thus placed on the flexible printed circuit board 600 are aligned onto the terminals 602a, 602b, 602c, and 602d of the same printed circuit board and are then heated with a soldering iron. As the terminals 505a, 505b, 505c, and 505d are heated with the soldering iron, solder bumps formed on the terminals 602a, 602b, 602c, and 602d melt, so that the terminals 505a, 505b, 505c, 505d and the terminals 602a, 602b, 602c, 602d, which are exposed from the aperture 506 of the insulating layer 502, are connected together by solder 508 so as to be covered substantially throughout the whole surface. All that is required for this soldering work is a mere fixing of the head suspension assembly to a jig. Thus, mass production can be effected even by manual operation, and therefore the device cost can be kept to a minimum.